Hydrogel Contact Research Articles

In Vitro Evaluation of Soft Contact Lens Wettability With a Nonmodified Commercial Videokeratoscope.

To evaluate a new in vitro technique for measuring soft contact lens wettability using a nonmodified commercial videokeratoscope, the Medmont E300. To this end, the capability of different artificial tears containing hyaluronic acid (HA) to improve soft contact lens wettability in vitro was investigated. An experimental in vitro study was conducted to assess the wetting properties of three artificial tears containing different concentrations of HA (0.1%, 0.2%, and 0.3%) on soft contact lenses. A saline solution was used as the control. For each solution, 15 hydrogel (Ocufilcon D) contact lenses and 15 silicone-hydrogel (Somofilcon A) contact lenses were evaluated. The in vitro wettability of the lenses was measured using the Medmont E300 with a self-developed technique, which involved measuring the tear film surface quality (TFSQ) mean, TFSQ area, TFSQ central, and TFSQ inferior. Compared with the saline solution, all the concentration of HA (0.1%, 0.2%, and 0.3%) improved the in vitro wettability of both soft contact lenses by decreasing their TFSQ mean and TFSQ area ( P <0.05). Regression models revealed an exponential relationship between contact lens wettability and the concentration of HA for both soft contact lenses ( R >0.5, P <0.05). Furthermore, the hydrogel contact lens presented a wetter surface than the silicone-hydrogel contact lens ( P <0.05). The measurement of in vitro wettability of soft contact lenses with a nonmodified Medmont E300 seems to be a useful technique to evaluate the wetting properties of contact lens products.

Patient Satisfaction and Tear Film Break-Up Time After First-Time Wearing of Silicone Hydrogel Contact Lenses.

The dryness and discomfort associated with soft contact lenses (SCLs) prevent their continued use. Recently, verofilcon A, a new daily disposable silicone hydrogel material SCL, was introduced, which has a high water content (surface water content of 80% or more) that overcomes the low water content drawback of silicone hydrogels. In this study, we evaluated the non-invasive tear break-up time (NIBUT) and comfort level in individuals wearing verofilcon A SCL for the first time. We enrolled 42 first-time SCL wearers, comprising 84 eyes. NIBUT was measured using the DR-1α® dry eye observation device at the state of the naked eye before SCL wear (baseline) and at one and four weeks after the first SCL wear. Additionally, we conducted a questionnaire survey during the fourth week to assess the comfort level (0-10) of SCL wear. Results:The NIBUT values were significantly higher at one week (10.8 ± 2.2 s, p<0.01) and four weeks (11.4 ± 2.2 s, p<0.01) after the first SCL wear than those at baseline (5.9 ± 2.0 s). Comfort level in SCL use was significantly higher at one week (9.0 ± 1.1, p<0.01) and four weeks (8.7 ± 1.2, p<0.01) than that at baseline (7.8 ± 1.8), and this level was higher regardless of the baseline NIBUT value. Prolonged BUT and increased comfort levels were observed in individuals wearing verofilcon A SCLs. Improvement in tear fluid retention was found to alleviate dry eye and discomfort, suggesting that verofilcon A may be a beneficial introductory lens for first-time SCL wearers.

Revolutionizing contact lens manufacturing: exploring cutting-edge techniques and innovations for enhanced vision and comfort

Abstract This review paper delves into the advancements and innovations revolutionizing contact lens (CL) manufacturing, focusing on techniques and technologies aimed at improving vision quality and wearer comfort. The article begins by tracing the evolution of CL fabrication techniques, paying homage to Leonardo da Vinci’s early contributions. It then discusses traditional methods such as lathe-cutting, spincasting, molded lens fabrication, and the recent advent of 3D printing in CL production. The review further explores advanced CL designs, including spherical, aspheric, toric, and bifocal/multifocal CLs, highlighting their specific applications and benefits. Material innovations in lens manufacturing are examined, with an emphasis on silicone hydrogel CL, hybrid lenses combining different materials, and the development of biocompatible and gas-permeable (GP) materials. Evaluation of optical design efficiency is another crucial aspect covered in this paper, encompassing visual acuity, contrast sensitivity, through-focus curves, reading performance, peripheral refraction, and patient-reported outcomes for quality of vision. Additionally, the role of nanotechnology and surface modifications in enhancing lens properties is explored, along with advances in lens coating and surface treatments, including antimicrobial and UV protection coatings. Nanocomposites of polymethyl methacrylate (PMMA) and TiO2 showed refractive indices between 1.52 and 1.59, while combining TiO2 NPs with poly(2-hydroxyethyl methacrylate) (PHEMA) yielded values ranging from 1.47 to 1.53. PGMA-TiO2 nanocomposites exhibited refractive indices between 1.47 and 1.50. Furthermore, nanocomposites of PVP-PVA-Ag with silver (Ag) NPs achieved higher refractive indices within the range of 1.45 to 1.49. This article concludes by discussing the challenges and future directions in CL manufacturing, focusing on addressing lens discomfort, improving oxygen permeability and moisture retention, and enhancing manufacturing efficiency and scalability. Overall, this review offers valuable insights into the cutting-edge techniques and innovations transforming CL production and paving the way for improved vision correction and wearer satisfaction.

Utilization Functional Analysis and Crosslinking Agents of Hydrogel Contact Lens Material according to Polymerization Method

Utilization Functional Analysis and Crosslinking Agents of Hydrogel Contact Lens Material according to Polymerization Method

Observation and assessment of the immediate use of a silicon hydrogel contact lens after transepithelial corneal cross linking: a prospective study

BackgroundTransepithelial corneal crosslinking (CXL) is a novel surgical approach for the treatment of keratoconus, which is a bilateral asymmetrical ophthalmological disease accompanied by progressive corneal ectasia. Silicon hydrogel (SiH) contact lenses have been extensively used in clinical ophthalmologic medicine, as a postoperative ophthalmological intervention. However, the ideal lens application duration after transepithelial CXL remains uncertain. Here, we aimed to investigate the effects and comfort of immediate corneal contact lens use after transepithelial CXL for keratoconus.MethodsIn this prospective study, 60 patients with keratoconus who underwent transepithelial CXL treatment were enrolled from September 2021 to January 2023 with a male:female ratio of 39:21, and an average age of 25.42 ± 5.47 years. The patients were divided randomly into two groups: group A contained 30 patients wearing silicone hydrogel contact lenses for 7 days postoperatively, and group B contained 30 patients wearing the same contact lenses for 3 days.Ten subjective ophthalmologic symptoms were surveyed by the patients, including pain, photophobia, foreign body sensation, tearing, burning, blurred vision, dry eyes, difficulty opening the eyes, astringency, and stinging. Ophthalmologic signs, including corneal edema and conjunctival congestion, were recorded by a single clinician on postoperative days 1, 3, and 7.ResultsEach surgical procedure was readily performed without complications, and both groups postoperative day 7 (P = 0.04), where group B scored (0.01 ± 0.41) lesser than group A (0.12 ± 0.29), whilst corneal edema in both groups recorded significantly different on postoperative days 5 and 7 (group A demonstrated the result of 0.17 ± 0.14 and 0.08 ± 0.11 for the respective days, whereas group B indicated 0.10 ± 0.13 and 0.03 ± 0.07 at the corresponding times).ConclusionsImmediate use of silicone hydrogel corneal lenses after transepithelial CXL effectively alleviates postoperative ocular distress, particularly with a three-day use period as the ideal duration.

Association of ocular surface and meibomian gland alterations with silicone hydrogel contact lens wear

PurposeTo evaluate silicone hydrogel contact lens (SH-CL) effects on the meibomian glands, corneal structure, and ocular surface parameters. MethodsFifty SH-CL wearers for at least 6 months, and 50 sex and age-matched control subjects were recruited for this cross-sectional study. Visual display terminal (VDT) work and CL wear duration were questioned, ocular surface and tear functions were evaluated using OSDI questionnaire, tear break-up time (TBUT), corneal fluorescein staining, and Schirmer test. Corneal sensitivity was measured with Cochet-Bonnet aesthesiometry. Meibography and in vivo confocal microscopy (IVCM) were performed to evaluate meibomian glands and corneal structure. Intergroup comparisons were made using the Chi-square test, Wilcoxon test, or Kruskal–Wallis test. ResultsIn the CL group, TBUT was shorter (P = 0.01), corneal fluorescein staining (P = 0.04), OSDI scores (P < 0.001), and meiboscores (P < 0.001) were higher than the control group. The biomicroscopic evaluation revealed meibomian gland dysfunction (MGD) in 34 % of the CL group and 20 % of the control group, which was not statistically significant (P > 0.05). IVCM showed that endothelial cell density was lower (P = 0.01) and polymegethism was higher (P < 0.001) in the CL group. Subbasal nerve density and corneal sensitivity measurements were similar in the two groups (P > 0.05). The longer VDT work duration was associated with increased CFS in the CL group (P = 0.05). ConclusionThe results showed that SH-CL wear increased dry eye symptoms and ocular discomfort, especially in longer VDT work duration. Meibography revealed significantly worse results in SH-CL wearers. SH-CL-related ocular discomfort seems to be more associated with MGD rather than neurosensorial alterations.

A Study on the Standardization of Tensile Strength Measurement Environment and Methods of Hydrogel Contact Lens

A Study on the Standardization of Tensile Strength Measurement Environment and Methods of Hydrogel Contact Lens

고함수율의 셀룰로오스 표면층을 갖는 실리콘 하이드로젤 콘택트렌즈의 제조 및 물성

고함수율의 셀룰로오스 표면층을 갖는 실리콘 하이드로젤 콘택트렌즈의 제조 및 물성

Superhydrophilic Poly(2-hydroxyethyl methacrylate) Hydrogel with Nanosilica Covalent Coating: A Promising Contact Lens Material for Resisting Tear Protein Deposition and Bacterial Adhesion.

Tear protein deposition and bacterial adhesion are the main drawbacks of the hydrogel contact lens. In this study, we developed a novel superhydrophilic poly(2-hydroxyethyl methacrylate) (NSCC-pHEMA) hydrogel with nanosilica covalent coating by the combination of colloidal silica immersion and dehydration treatment. The infrared spectroscopy and energy dispersive X-ray spectroscopy analyses confirmed the successful formation of Si-O covalent bonding between nanosilica and pHEMA hydrogel. This coating was highly stable against powerful sonication or long-term shaking immersion treatment. Among various NSCC-pHEMA hydrogels with different colloidal silica concentrations, the 7%NSCC-pHEMA hydrogel generated a superhydrophilic micro wrinkle surface with a root-mean-square roughness of 43.10 nm, which dramatically reduced the deposition of lysozyme and bovine serum albumin by 65% and 57%, respectively, and decreased the adhesion of S. aureus and E. coli by 59% and 66%, respectively, in comparison to the pHEMA hydrogel. However, the nanosilica coating had little effect on the mechanical properties, light transmittance, oxygen permeability, and equilibrium water content of the pHEMA hydrogel. NSCC-pHEMA hydrogels were nontoxic to both mouse fibroblasts (L929) and human immortalized keratinocytes (HaCaT). Thus, the superhydrophilic NSCC-pHEMA hydrogel is a potential contact lens material for resisting tear protein deposition and bacterial adhesion.

Optical Quality and Visual Performance With Different Toric Contact Lens Designs.

To evaluate the optical quality of different toric contact lens (CL) designs and compare their on-eye visual correction performance. Twenty soft CL wearers aged 20 to 39 years were enrolled. Two daily disposable silicone-hydrogel toric CLs were tested: the "Eyelid Stabilized Design" (ESD-CL) and prism-ballast design (PB-CL); a spherical daily disposable silicone hydrogel CL (spherical CL) was used as a control. On-eye performance was compared for corrected distance visual acuity (CDVA), astigmatism, and ocular higher-order aberrations (HOAs); astigmatism and ocular HOAs were measured with a wavefront sensor. The subjective quality of vision, rated for "blurred vision" and "double vision," lens rotation, and fitting were also compared. The ESD-CLs, PB-CL, and no-CL provided better CDVA than spherical CL ( P <0.05). Compared with spherical CL and no CL, PB-CL and ESD-CLs caused significantly lesser astigmatism ( P <0.05). Coma was significantly lesser with ESD-CLs than that with PB-CL ( P <0.05); total HOAs did not differ among the four conditions. The subjective ratings for blurred and double vision were significantly lower with ESD-CLs than those with spherical CL ( P <0.05). Toric CLs provide a better CDVA than spherical CLs. However, differences in coma and subjective symptoms may occur because of the design of toric CLs.

Hydrogel Contact Lenses Embedded with Amine-Functionalized Large-Pore Mesoporous Silica Nanoparticles with Extended Hyaluronic Acid Release.

Contact lenses (CLs) have emerged as an effective method for delivering ophthalmic drugs. In this research, we designed hydrogel CLs capable of extended release, utilizing large-pore mesoporous silica nanoparticles (LPMSNs) to deliver hyaluronic acid (HA) for treating dry eye syndrome. LPMSNs were functionalized with amine groups (LPMSN-amine) to enhance HA loading and release capacity. In vitro release studies demonstrated that LPMSN-amine CLs exhibited superior slower HA release than LPMSN-siloxane and standard CLs. Within 120 h, the cumulative amount of HA released from LPMSN-amine CLs reached approximately 275.58 µg, marking a 12.6-fold improvement compared to standard CLs, when loaded from 0.1 wt% HA solutions. Furthermore, LPMSN-amine CLs effectively maintained moisture, mitigating ocular surface dehydration, making them a promising solution for dry eye management. This study successfully developed LPMSN-amine CLs for extended HA release, identifying the optimal functional groups and loading conditions to achieve sustained release.

Biomimetic-Engineered Silicone Hydrogel Contact Lens Materials.

Contact lenses are one of the most successful applications of biomaterials. The chemical structure of the polymers used in contact lenses plays an important role in determining the function of contact lenses. Different types of contact lenses have been developed based on the chemical structure of polymers. When designing contact lenses, materials scientists consider factors such as mechanical properties, processing properties, optical properties, histocompatibility, and antifouling properties, to ensure long-term wear with minimal discomfort. Advances in contact lens materials have addressed traditional issues such as oxygen permeability and biocompatibility, improving overall comfort, and duration of use. For example, silicone hydrogel contact lenses with high oxygen permeability were developed to extend the duration of use. In addition, controlling the surface properties of contact lenses in direct contact with the cornea tissue through surface polymer modification mimics the surface morphology of corneal tissue while maintaining the essential properties of the contact lens, a significant improvement for long-term use and reuse of contact lenses. This review presents the material science elements required for advanced contact lenses of the future and summarizes the chemical methods for achieving these goals.

Study of silicone hydrogel contact lenses’ surface reflection characteristics using confocal microscopy

The physical and chemical properties of contact lenses (CLs) differ significantly from one another. This is already covered by the FDA classification, which divides soft lenses into groups and subgroups for additional characteristics. The differences relate to both the interior and surface of the lens. Several differences in the surface characteristics of individual contact lenses have been studied and demonstrated to date. However, one of their fundamental physical properties, that is light reflection or, quantitatively, reflectance has not been compared. This paper describes the surface differences of a range of silicone-hydrogel (SiHy) lenses using reflectance confocal microscopy. It shows the relationship between the amount of light reflected from the lens surface and the material parameters. Common SiHy lens materials were used in the study, including two lenses with surface modifications. Light incident at the interface between two media (phosphate-buffered saline and lens) with different refractive indices is partially reflected. The normalized results show significant differences between the reflection signals (1 vs 0.07), and that they are not correlated with the refractive index (R2 = 0.5536). For the water content (%H2O), a general trend was observed that the higher the %H2O, the lower the reflection signal is (R2 = 0.8105). The reflection signal and surface modulus show the best correlation. (R2 = 0.9883). The proposed CLs analysis method, using reflectance confocal microscopy, provides data to differentiate between lenses with and without surface modifications.

Polyacrylic Acid Hydrogel Coating for Underwater Adhesion: Preparation and Characterization.

Underwater adhesion involves bonding substrates in aqueous environments or wet surfaces, with applications in wound dressing, underwater repairs, and underwater soft robotics. In this study, we investigate the underwater adhesion properties of a polyacrylic acid hydrogel coated substrate. The underwater adhesion is facilitated through hydrogen bonds formed at the interface. Our experimental results, obtained through probe-pull tests, demonstrate that the underwater adhesion is rapid and remains unaffected by contact pressure and pH levels ranging from 2.5 to 7.0. However, it shows a slight increase with a larger adhesion area. Additionally, we simulate the debonding process and observe that the high-stress region originates from the outermost bonding region and propagates towards the center, spanning the thickness of the target substrate. Furthermore, we showcase the potential of using the underwater adhesive hydrogel coating to achieve in-situ underwater bonding between a flexible electronic demonstration device and a hydrogel contact lens. This work highlights the advantages of employing hydrogel coatings in underwater adhesion applications and serves as inspiration for the advancement of underwater adhesive hydrogel coatings capable of interacting with a wide range of substrates through diverse chemical and physical interactions at the interface.

Inflammation-responsive molecular-gated contact lens for the treatment of corneal neovascularization

Corneal neovascularization (CNV) badly damages the corneal transparency, resulting in visual disturbance and blindness. The frequent administration of glucocorticoid eye drops in clinical increases the possibility of side effects and reduces patient compliance. Considering CNV is often accompanied by an increase in ROS production, a ROS-responsive monomer 2-(methylthio)ethyl methacrylate was introduced into the matrix as a “gating switch”. The prepared dexamethasone contact lenses (MCLs@Dex) showed a significant H2O2-responsive release for 168 h. To avoid corneal hypoxia and neovascularization caused by long-term wearing, high‑oxygen-permeability fluorosiloxane materials were incorporated. The oxygen permeability of MCLs@Dex was 4 times that of commercially available hydrogel contact lenses and had ultra-low protein adsorption, which meets the requirements of long-term wearing. In vivo pharmacokinetic studies showed that MCLs@Dex increased the mean residence time by 19.7 times and bioavailability by 2.29 times compared with eye drops, validating the ROS response and sustained release properties. More importantly, MCLs@Dex had satisfactory effects on reducing inflammation and decreasing the related cytokines and oxidative stress levels, and demonstrated significant inhibition of neovascularization, with a suppression rate of 76.53% on the 14th day. This responsive drug delivery system provides a promising new method for the safe and effective treatment of ocular surface diseases.

Nanoparticle-laden contact lens for controlled release of vancomycin with enhanced antibiotic efficacy

Vancomycin is the last resort antibiotic for the treatment of severe bacterial keratitis. Its clinical application is limited due to its hydrophilicity and high molecular weight. To overcome this, this study aims to develop nanoparticles-laden contact lens for controlled ocular delivery of vancomycin. Polyvinyl alcohol (PVA) was used as encapsulant material. The nanoparticles had a negative surface charge and an average size of 147.6 nm. A satisfactory encapsulation efficiency (61.24%) was obtained. The release profile was observed to be slow and sustained, with a release rate of 1.29 μL mg−1 h−1 for 48 h. Five out of 6 test bacteria were suppressed by vancomycin nanoparticles-laden contact lens. Vancomycin is generally ineffective against Gram-negative bacteria and unable to pass through the outer membrane barrier. In this study, vancomycin inhibited Proteus mirabilis and Pseudomonas aeruginosa. Nano-encapsulation enables vancomycin to penetrate the Gram-negative cell wall and further destroy the bacterial cells. On Hohenstein challenge test, all test bacteria exhibited significant reduction in growth when exposed to vancomycin nanoparticles-laden contact lens. This study created an effective and long-lasting vancomycin delivery system via silicone hydrogel contact lenses, by using PVA as encapsulant. The antibiotic efficacy and vancomycin release should be further studied using ocular in vivo models.

Corneal sensitivity in silicone hydrogel and rigid gas permeable contact lens wear

PurposeThe aim of this prospective cross-sectional cohort study was to test the effect of silicone hydrogel (SH) and rigid gas permeable (RGP) contact lens (CL) wear on corneal sensitivity, applying the new Swiss Liquid Jet Aesthesiometer for Corneal Sensitivity (SLACS) and the Cochet-Bonnet (CB) aesthesiometer, based on subject feedback (psychophysical method). MethodsParticipants were recruited for three equally large groups: Group A (SH CL), Group B (RGP CL) and Group C (non-CL wearers). Inclusion criteria were healthy eyes and OSDI ≤ 13. Corneal sensory thresholds were determined twice during two visits, with aid of SLACS and CB. Results96 participants completed the study (n = 33 in groups A and C, n = 30 in group B); average age in group A: 27.42 ± 6.83 years, group B: 36.90 ± 9.68 years and group C: 26.06 ± 6.19 years. No statistically significant difference in corneal sensitivity was observed between the three groups for either method (p = 0.302 for SLACS, p = 0.266 for CB; Kruskal-Wallis rank sum test). Higher CSTs were obtained for males than for females in both CL groups with SLACS, and with CB only in the RGP CL group (p = 0.041 in Group A, p = 0.006 in Group B with SLACS; p = 0.041 in Group B with CB; bootstrap analysis with age correction and gender balancing). No correlation was observed between CL comfort and corneal sensitivity for neither method applied (for SLACS r = 0.097 and p = 0.51, for CB r = 0.17 and p = 0.15; robust linear mixed model). ConclusionsNo difference in corneal sensitivity with CL compared to non-CL wear was noted in this study. However, lower levels of corneal sensitivity were observed in the male CL groups, warranting further investigation.

Tear film dynamics of a new soft contact lens.

To present the objective metrics from a study that evaluated the clinical performance of a senofilcon A contact lens, both with and without a new manufacturing technique. This was a single-site, five-visit, controlled, randomised, subject-masked, 2 × 2 crossover study (May-August 2021) with a 2-week lens dispensing period (bilateral wear) and weekly follow-up visits. Healthy adult (18-39 years), habitual spherical silicone hydrogel contact lens wearers were included. The High-definition (HD) Analyzer™ was used to objectively measure the lens-on-eye optical system resulting from the study lenses at 1-week follow-up. Measurements assessed were vision break-up time (VBUT), modulation transfer function (MTF) cutoff, Strehl ratio (SR), potential visual acuity (PVA) for 100% contrast and objective scatter index (OSI). Of the 50 enrolled participants, 47 (94.0%) were randomly assigned to one of the two possible lens wear sequences (test/control or control/test) and dispensed at least one study lens. The estimated odds ratio of VBUT > 10 s was 1.582 (95% confidence interval [CI]: 1.009 to 2.482) in test versus control lens. The least squares mean difference estimates of MTF cutoff, SR and PVA for 100% contrast between test versus control lens were 2.243 (95% CI: 0.012 to 4.475), 0.011 (95% CI: -0.002 to 0.023) and 0.073 (95% CI: -0.001 to 0.147), respectively. The estimated ratio of median OSI between test versus control lens was 0.887 (95% CI: 0.727 to 1.081). The test lens demonstrated superiority over the control lens with respect to VBUT and MTF cutoff. No serious adverse events were reported; eight adverse events (three ocular, five non-ocular) were indicated by six participants during the study. The test lens demonstrated an increased probability of having a longer VBUT (>10 s). Future studies may be designed to assess the efficacy and long-term use of the test lens in a larger population.

Chromatic dispersion of soft contact lens materials

PurposeTo investigate and evaluate the chromatic dispersion of various hydrogel and silicon hydrogel contact lens materials. MethodsEighteen different soft contact lens materials with high and low water content in lens power of −1.00 DS were measured by one operator at temperature of 20 °C ± 0.5° soaked in ISO standard phosphate-buffered saline (PBS) and in their respective packaging solutions (PS). An analogue Abbe refractometer (Model Zuzi 320, AUXILAB, S.L., Navarra, Spain) was used for refractive index (RI) measurements at 5 different wavelengths. All contact lenses were presented in a random and masked order to the operator. The Bland-Altman method with 95 % limits of agreement (LoA) and coefficient of repeatability (CoR) was used to characterise the repeatability of refractive index measurements. The Abbe numbers for each material were calculated by entering the measured and interpolated refractive indices into the Abbe number equation. One-way ANOVA analysis was used to test if there were significant differences between the 5 different wavelengths (470 nm–680 nm) within each material. An unpaired t-test was used to determine if there were differences in refractive index or dispersion between packaging solution and PBS results. ResultsNelfilcon A (Dailies Aqua Comfort Plus) soaked in PS showed the best repeatability of all 18 examined soft contact lenses across all wavelengths with an average refractive index of 1.3848 for all 6 contact lenses with a standard deviation of 0.00064. The 95 % limits of agreement were between 1.3835 and 1.3860. The mean coefficient of repeatability for nelfilcon A was 0.00125. For contact lenses soaked in ISO Standard PBS comfilcon A (Biofinity) had the best repeatability. The average refractive index of all 6 contact lenses was 1.4041 with a standard deviation of 0.00031 and a coefficient of repeatability of 0.00060. The 95 % limits of agreement were between 1.4035 and 1.4047. The analysis with One-way ANOVA with multiple comparisons involving Holm-Sidak post-hoc, showed that there are significant differences (p < 0.001, Fratio = 376.2 between wavelengths and Fratio = 1559 between different refractive indices) in the refractive index of most common lens materials across the visible wavelength range. Based on unpaired t-test, there is no significant difference (p > 0.05) in the Abbe numbers of the tested lens materials whether they have been placed in the packaging solution or in standard PBS (p > 0.05, 95 % CI = −4.8070 to 5.8680, t = 0.2054). The Abbe numbers for the calculated contact lenses soaked in PS ranged between 43.7 and 89.9. For contact lenses stored in PBS the range was between 46.3 and 81.6. ConclusionThere is a good repeatability between repeated RI measurements taken from the same lens and from the same material. The significant differences between the refractive indices across the 5 different wavelengths showed the presence of chromatic dispersion in the 18 evaluated soft contact lens materials. Furthermore, it could be shown that there is no significant difference in dispersion whether the contact lenses are soaked in standard PBS or in their respective packaging solutions. With no other published data available as a reference, absolute accuracy of the calculated Abbe numbers remains to be confirmed, however, this study did confirm that significant chromatic dispersion exists in soft contact lens materials.

Simultaneous correction of primary aberrations through wearing silicone hydrogel contact lens

Simultaneous correction of primary aberrations through wearing silicone hydrogel contact lens